*   Fix `Class#descendants` and `DescendantsTracker#descendants` compatibility with Ruby 3.1.

    [The native `Class#descendants` was reverted prior to Ruby 3.1 release](https://bugs.ruby-lang.org/issues/14394#note-33),
    but `Class#subclasses` was kept, breaking the feature detection.

    *Jean Boussier*

Please check [7-0-stable](https://github.com/rails/rails/blob/7-0-stable/activesupport/CHANGELOG.md) for previous changes.